Question

I’m studying Java basics from the beginning. But there is still some theoretical basis.

How do I calculate the average of each student in the example below?

    package teste01classes;

    public class Metodos {

        static void Media(Alunos[] aluno) {
            // SEE HERE.
            double[] media;
            for (int i = 0; i < aluno.length; i++) {
                media[i] = (aluno[i].n1 + aluno[i].n2 + aluno[i].n3) / 3;
                System.out.println(aluno[i].nome + media[i]);
            }
        }
    }



package teste01classes;

// Classe Alunos com os campos
public class Alunos {
    String nome;
    int n1, n2, n3;
}



package teste01classes;

public class Teste01Classes {

    public static void main(String[] args) {

        Alunos[] aluno = DadosAlunos.createAlunos();

    }
}

Answer 1

You have to initialize the media array, and then return it:

static double[] media(Alunos[] aluno) {
  // allocate memory for a double array of size aluno.length
  double[] media = new double[aluno.length];
  for (int i = 0; i < aluno.length; i++) {
    media[i] = (aluno[i].n1 + aluno[i].n2 + aluno[i].n3) / 3;
    System.out.println(aluno[i].nome + media[i]);
  }
  return media;
}

Then, in your main, invoke it:

public static void main(String[] args) {
  Alunos[] aluno = DadosAlunos.createAlunos();
  double[] medias = Metodos.media(aluno);
}